DE 10 2008 054 240 A1 describes a rotor of a mechanical automotive vacuum pump. The rotor is defined by a rotor body which is provided with a vane slit for supporting a slidable pump vane. The rotor body is provided with a coupling structure at a coupling-sided end portion of the rotor body and is provided with a cylindrical radial bearing surface at the same coupling-sided end portion. The rotor body is provided with a second radial bearing at the vane-sided end portion of the rotor body. The second radial bearing is provided with a cylindrical bearing portion for defining a second radial friction bearing at the vane-sided end of the rotor body. Production costs are considerable since two separate radial bearings are provided.